Upon seeing the above picture, I believe all friends in the industry can see that this is AISI 1040 steel, which is a high carbon steel. Under a microscope, the clear image of 400X shows that the microstructure is composed of uniformly distributed pearlite and ferrite areas, with visible grain boundaries. This beautiful high carbon steel sample was inlaid by an American MetLab metallographic inlay machine, with good edges and no defects. It's great!